Side effects of titanium dioxide topical include dry skin, and rare side effects include irritated skin, inflamed hair follicles and allergic reactions, states WebMD. Dry titanium dioxide powder is highly toxic to humans inhaling it, and an international agency has classified it as possibly carcinogenic, states the American Cancer Society.
Some sunscreen products use titanium dioxide in a tiny particle form called nanoscale, which is thousands of times smaller than dust particles typically present in homes, explains the American Cancer Society. Titanium dioxide blocks ultraviolet rays effectively, but experts do not know the long-term effects of the tiny particles passing through human skin and into the bloodstream. Animal research indicates the possibility that the particles can cause significant inflammation.